Temperature sintering effects on the magnetic, electrical and transport properties of La<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub>/Nd<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub> composites
Y L Chang; C K Ong; Y L Chang; Department of Physics, National University of Singapore, 10 Kent Ridge Cresent, 119260, Singapore; C K Ong; Department of Physics, National University of Singapore, 10 Kent Ridge Cresent, 119260, Singapore
Журнал:
Journal of Physics: Condensed Matter
Дата:
2004-06-02
Аннотация:
The microstructure, magnetic and electrical transport properties of La<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub>/Nd<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub> composites are studied as a function of sintering temperature. At 900 °C, the intergrain exchange couplings between the adjacent particles give rise to an increase in resistance. Raising the sintering temperature induces the formation of an interfacial phase near the La<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub> and Nd<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub> grain boundaries as indicated in the XRD pattern and SEM image. At 1100 °C, the formation of interfacial phases near the grain boundaries enhances the conductivity in the composite. Broad magnetoresistance across room temperature is observed in a composite sintered at 1300 °C. This observation may be ascribed to the coexistence of multiphase in the composite which leads to a decrease in resistance. The results suggest that sintering temperature has a prominent effect on the properties of the grain boundary, which plays an important role in determining the electrical transport behaviour of the composites.
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